Multi-Analytical Characterization and Human Health Risk Assessment of Heavy Metals, Phthalate Plasticizers, and Ether Contaminants in Commercial Synthetic Hair Extensions

Abstract

Despite their benefits, synthetic hair products are used globally for their affordability, durability, and aesthetic appeal. However, there have been concerns about their chemical composition and the potential health hazards they pose due to the dangerous chemicals they contain. This study aimed to extensively examine the physicochemical parameters, heavy metals, phthalate plasticisers, chlorinated ether compounds, polymer composition, human exposure, and potential health risks of all commercial synthetic hair products available in Delta State, Nigeria. Twenty-eight products were subjected to a multimodal laboratory method of physicochemical characterisation, including Atomic Absorption Spectrometry (AAS), Gas Chromatography–Mass Spectrometry (GC–MS), Fourier Transform Infrared Spectroscopy (FTIR), chemometric analyses, and exposure and health risk models, in accordance with USEPA guidelines. The results indicated that the pH levels ranged between 6.90 and 8.70. Heavy metal analysis revealed the presence of lead (0.017-0.031mg/L) and Cadmium (0.006-0.017mg/L) in all the samples analysed, while the levels of chromium and arsenic were not detectable. DEHP appeared to be the most abundant organic contaminant, and FTIR confirmed the presence of polymer functional groups consistent with polymer additives such as plasticisers and chlorinated compounds. More than 99% of the total variance was explained by Principal Component Analysis, revealing distinct patterns of manufacturing-related contaminants. While Hazard Quotients, Hazard Indices, and Lifetime Cancer Risks were not identified as potential risks, Contamination Burden levels were detected within the detectable range and warrant attention regarding potential chronic exposure with prolonged use. These results offer valuable data for better product surveillance, manufacturing quality management, evidence-based regulation, and, ultimately, the protection of consumers' health.